Concrete body



(No Model.)

D. J. MARSTON.

CONCRETE BODY.

Patented July 29, 1890.

TNE norms PEYEHS col, PHOTO-LITHOV, WASNWGTON, n. c.

UNITED STATES PATENT OFFICE.

DUDLEY J. MARSTON, OF AMESBURY, MASSACHUSETTS.

CONCRETE BODY.

SPECIFICATION forming part of Letters Patent No. 433,014, dated July 29, 1890.

Application filed July 18, 1889. Serial No. 317,915- (No specimens.)

To all whom it may concern.-

Be it known that I, DUDLEY J. MARSTON, ofAmesbury, in the county of Essex and State of Massachusetts, have invented a new and useful Improvement in Concrete Bodiesavhich will, in connection with the accompanying drawings, be hereinafter fully described, and specifically defined in the appended claim.

In said drawings, Figure 1 is a perspective view showing a concrete block formed according to my invention, the core being indicated by dotted lines. Fig. 2 is a section taken transversely through the block shown in Fig. l. in the cored portion thereof. Fig. 3 is a longitudinal section through Fig.1 in the cored portion thereof, the central portion being broken away in order to increase the scale.

This invention relates to bodies formed of hydraulic cement or other self -hardening plastic material, which, when hardened by drying,is practicallyimpervious to moisture; and it consists in forming such bodies with an outer wall or shell of sufficient thickness,

with an inclosed space or chamber filled with the products of combustion of pit-coalthat is, the ashes and cinders-the latter being preferably broken into pieces if of large size, which will aid in resisting the pressure and shocks to which such bodies may be subjected, and will yet yield slightly to the contractile action of the inclosing-wall when the latter is subjected to the action of severe cold.

Referring again to said drawings, A represents a block of the kind above specified, a a representing the two broader or side walls, I) b the edge walls, and c c the end walls, while B represents the core or filling, which, as already stated, consists of the products or residuum of pit-coal (anthracite or bituminous) after being burned in any of its common uses. Said block may represent a doorstep, a buildingblock, or for other uses for which concrete bodies are employed; and in carrying my invention in to practical use I can employ it in the preparation of pillars, posts, ornaments, and all the various forms, having the requi site thickness, which are created from plastic, self-hardening, and durable material.

Among the advantages of my invention are the following: First, the saving in cost, as

the filling in, so far as it takes the place of cement, is a clear gain, as the material for the filling is otherwise valueless; second, that when such bodies are formed with an internal chamber the wall hardens more perfectly, and hence, bulk for bulk, are stronger than when solid; third, the cost of handling and transportation and danger of breaking is largely reduced and, fourth, the danger of injury from intense cold is much less than in solid bodies.

The thickness of the concrete shell should be varied according to conditions of use, the size of the body, and the strain to which it is to be subjected.

As a well-known means of molding and forming hollow bodies, I preferably employ an external mold, the internal dimensions whereof accord with the desired external form of the concrete body to be produced. In this mold I arrange and supporta wooden core, which is of the size and form of the desired cavityin the concrete block. Said core I prefer to support at one end only, as then the opposite end may be as far from the end of the external mold as the intended thickness of the shell of the concrete body. I form said core slightly tapering, so that it may be readily withdrawn at the proper time, and I coat it with oil before using to facilitate withdrawal. The core being secured in place in the mold. I fill the space between the two with the prepared concrete that forms the shell of the block, and when the same is slightly set I withdraw the core, then fill the space it occupied with the described filling to within the proper distance of the end of the block, and the balance of the'space I fill with concrete, like the rest of the shell, thus completing a continuous shell of uniform thickness all around the filling.

To insure .the close packing of the ashes, I prefer to moisten the same to such degree as to mainly expel the air therefrom. After the interior has been filled and the open end closed, as stated, the block remains in the mold for about four hours, according to the rapidity of its hardening, when the exterior mold is removed and the block allowed to fully harden.

In preparing the concrete matter for the external wall of these blocks I mix with the IOC hydraulic cement a proper quantity of sand, ducts of combustion of pit-coal duly comgravel, or broken stone, according to the use pacted therein to aid in resisting the pressure 10 to which the block is to be applied. to which the shell is subjected, substantially I claim as my inventionas specified. 5 As anew article of 1nanufacture,abuildingblock or other article formed with a shell of \Vitnesses: hydraulic cement duly compounded, with an G. N. BRIGGS, interior chamber or space filled with the pro- FRED A. BROWN.

DUDLEY J. MARSTON. 

